Bynes: 'So, um… about those Rihanna tweets…'

Amanda Bynes claims her Rihanna bashing tweets were fake.

The 27-year-old actress recently launched a Twitter attack on the 25-year-old singer, saying Chris Brown beat her up in 2009 because she is "not pretty enough" and while the tweets were sent from Amanda's own account, she has now backtracked and denied writing the offensive messages.

She wrote: "I saw a bunch of mocked up tweets about me bashing Rihanna in my mentions. I'm followed by so many people that someone is always mocking up fake tweets so I feel the need to address them!"

Amanda, who was charged with attempted evidence tampering, reckless endangerment and marijuana possession in court last week, after being arrested at her New York City apartment, then went on to blast Rihanna for allegedly smoking marijuana.

She added: “"That's one of the mocked up images, they took photos of me from outside and morphed them onto someone else's body. I am allergic to marijuana and alcohol but I smoke tobacco. Why does Rihanna smoke weed and not get in trouble for it but I smoke tobacco and people think I'm on drugs?

"I refuse to be treated like someone I'm not, which is why I fought for myself and am suing everyone involved.

"I don't need to go to rehab. There is never a drug or alcohol in my system!

"I'm sick of all the lies!"